Acceleration and free fall problem

In summary, using the given information of Rachel dropping from a 5m high dive, with an acceleration of -9.8m/s^2, and starting from rest, it takes her 1.10 seconds to hit the surface of the water and she is traveling at a velocity of -9.9m/s when she hits the water.
  • #1
cheerspens
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Homework Statement


Rachel drops straight off a high dive whose board is 5 meters above the surface of the water. How long does it take Rachel to hit the surface of the water? How fast is Rachel traveling when she hits the surface of the water?


Homework Equations





The Attempt at a Solution


I made an x vs. t graph, a v vs. t graph, and an a vs. t graph.
My variable list is as follows:

x at time 0(initial location)=5m
x(location) at end time=0m
initial velocity= is unknown
Velocity at end=0m/s
time=is unknown
acceleration=-9.8m/s^2 (which is free fall)
 
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  • #2
The graphs, although conceptual, do little to help you get into the meat of the equations. Review your core kinematics equations, and choose which ones contain the variables you need to solve for.

Also, her initial velocity is zero (she starts from rest, and drops straight down). Her velocity the moment before she hits the water is the one you want to solve for.
 
  • #3
Would my answers to these questions for this problem be correct:
How long does it take Rachel to hit the surface of the water?
1.10 sec

How fast is Rachel traveling when she hits the surface of the water?
-9.9m/s
 

FAQ: Acceleration and free fall problem

1. What is acceleration?

Acceleration is the rate at which an object's velocity changes over time. It is typically measured in meters per second squared (m/s2).

2. How do you calculate acceleration?

Acceleration can be calculated by dividing the change in velocity by the change in time. The formula for acceleration is a = (vf - vi) / t, where a is acceleration, vf is final velocity, vi is initial velocity, and t is time.

3. What is free fall?

Free fall is the motion of an object when it is only affected by the force of gravity. In a free fall, the object's acceleration is equal to the acceleration due to gravity, which is approximately 9.8 m/s2 on Earth.

4. How do you solve a free fall problem?

To solve a free fall problem, you need to know the object's initial velocity, acceleration due to gravity, and time. Using the formula for acceleration, you can calculate the final velocity of the object, as well as its position after a certain amount of time.

5. What is terminal velocity?

Terminal velocity is the maximum velocity that a falling object can reach when the force of air resistance is equal to the force of gravity. In other words, it is the point at which the object stops accelerating and falls at a constant speed.

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